1. Field of the Invention
The present invention relates to an illumination system, and more particularly to an illumination system having multiple lamps.
2. Description of Related Art
Referring to FIG. 1, a conventional illumination system 100 comprises a first lamp 110, a second lamp 120, and a reflective component 130. The first lamp 110 and the second lamp 120 are disposed oppositely each other and located on a same axis 50. The reflective component 130 is disposed between the first lamp 110 and the second lamp 120. The reflective component 130 has two reflective surfaces 132 and 134. The reflective surfaces 132 and 134 respectively have a 45 degree angle with the axis 50.
The first lamp 110 comprises a burner 112 and a parabola lampshade 114, and the second lamp 120 comprises a burner 122 and a parabola lampshade 124. The burners 112 and 122 are respectively adapted to provide a divergent beam The parabola lampshades 114 and 124 are adapted to converge the divergent beam into parallel beams 112a, 122a. The optical axes of the parallel beams 112a and 122a are parallel to the axis 50. Moreover, after being reflected at the reflective surfaces 132 and 134 of the reflective component 130, portions of the two parallel beams 112a and 122a are combined into a combined beam 140. The remaining portions of the parallel beams 112a and 122a are reflected by the parabola lampshades 114 and 124 back to the reflective component 130 and then reflected at the reflective surfaces 132 and 134 to combine into the combined beam 140.
In the above-described double-lamp illumination system 100, the burners 112 and 122 are relatively easily destroyed by overheating, as the parallel beams 112a and 122a repetitively pass through the burners 112 and 122, and directly irradiate the second lamp 120 and the first lamp 110. Furthermore, in case one of the lamps is broken, portions of images projected by a projector employing such an illumination system are dark.
Furthermore, lamps providing parallel beams, such as the lamps having parabola lampshades, can be used in the double-lamp illumination system 100, but lamps providing non-parallel beams, such as the lamps having elliptic lampshades, can not be used in the double-lamp illumination system 100. In addition, portions of the parallel beams provided by the double-lamp illumination system 100 can be divergent and cannot be effectively utilized. Thus, a brightness of the images projected by the projector employing a double-lamp illumination system 100 is decreased. Furthermore, because the volume of the double-lamp illumination system 100 is bulkiness, the projector employing the illumination system 100 can not achieve designing principles of miniaturization and light for electronic products.